Just because a manufacturer says you need 600W or somethin PSU it doesn't necessarily make it so. This whole marketing bul***** about PSUs is dumb as brick. Very roughly said, unless you run VGA cards in SLI and have dozen of other devices, you don't need anything over 500 at all. I have C2D CPU, 4GB RAM, two hard disk, extra network and soundcard, Radeon 5850, and even the 425W PSU I have is huge overkill.